09 KLR Throttle Hesitation - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

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post #1 of 10 Old 03-28-2020, 11:53 PM Thread Starter
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09 KLR Throttle Hesitation

Hey Gang,

I’ve got an ‘09 KLR 650 with 11k miles on it, about 4K of which we’re put on by me. Loving the bike (pic below just because) but today on the trail and highway ran into an issue: every once in awhile, the throttle would “hesitate” a little. The exact same feeling I get when I’m running out of gas right before switching to reserve. It would hesitate a little (just a few seconds) and then open up and run fine for another few minutes. On and off with no real consistency over the few hours I was riding today. Happened on the trail at low speeds, highway at fast speeds, high and low RPMS, again, no predictability fo the cause that I could tell.

Any ideas what could cause this that I should check first? Pinched vent line? Clogged air filter? Carb?




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post #2 of 10 Old 03-29-2020, 07:22 AM
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The smallest particle in the carb can cause this ... Clean it. I had a friend go through exactly the same thing ... He removed and cleaned the carb trailside. It was perfect after that ...
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post #3 of 10 Old 04-01-2020, 07:13 PM
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I had a similar problem last year, mine was the diaphragm in the fuel shut off valve was being softened by the alcohol in the fuel. I put a manual fuel valve on it an all good. Easy upgrade.
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Last edited by Jknight611; 04-01-2020 at 07:14 PM. Reason: Fight with spellcheck
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post #4 of 10 Old 04-04-2020, 01:26 PM Thread Starter
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Okay so I finally got some time to do a quick clean of the carb, found a little gray spec of crap in the bowl - not sure if that would be enough to caused problems but I could see that getting pulled up into the jet.



Only problem now: put everything back together after cleaning and my bike won’t start! I keep flooding the carb, draining it, bike will start and run at high throttle but stalls at idle, carb floods, repeat.

I’m guessing I screwed up the position of my pilot mixture screw when I pulled it thinking I needed to clean it. Any idea how to set that bad boy?


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post #5 of 10 Old 04-04-2020, 02:04 PM
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If the symptoms in your first post happened at very low speed on the trail and low small throttle openings on the street, they would be consistent with flooding.

If your carburetor keeps flooding it has to be that the inlet valve is not closing as it should, indicating it has some crap lodged in it or the tip of the needle is damaged.

Try this:

Close the petcock. Drain the carburetor bowl. Keep the petcock closed. Hit the starter button, open the petcock and count to three, then shut off the petcock. The bike should have started and enough gas should have gone into the bowl to allow it to run for a bit. If not, do it again and count to five.

When the engine is running and the petcock is closed, see if it will operate normally in response to the throttle. It should. When it starts to falter as if it is running out of gas, open the petcock. Let it idle. If it floods, it is surely your inlet valve.

The inlet valve seat should be cleaned with a q-tip and a bit of polishing compound and the needle should be removed from the float and inspected. If it appears hardened or has a worn ring, replace it. If not, gently wipe it and reinstall it.

Don't mess with your idle mix needle until you have this flooding under control.

Tom [email protected]

“On the way downtown I stopped at a bar and had a couple of double Scotches. They didn't do me any good. All they did was make me think of Silver-Wig, and I never saw her again.” -Philip Marlowe

“'Why' and 'How' are words so important they cannot be too often used.” -Napoleon Bonaparte

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Last edited by Tom Schmitz; 04-04-2020 at 02:07 PM.
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post #6 of 10 Old 04-04-2020, 02:41 PM
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Did you by any chance CAP the upper LH plastic fitting?
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post #7 of 10 Old 04-04-2020, 03:10 PM
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Initial setting for the pilot mixture screw is 2 turns open from lightly seated. But you've got to fix the flooding issue 1st, as Tom said.
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pdwestman
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post #8 of 10 Old 04-04-2020, 05:26 PM Thread Starter
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Quote:
Originally Posted by Tom Schmitz View Post
If the symptoms in your first post happened at very low speed on the trail and low small throttle openings on the street, they would be consistent with flooding.

If your carburetor keeps flooding it has to be that the inlet valve is not closing as it should, indicating it has some crap lodged in it or the tip of the needle is damaged.

Try this:

Close the petcock. Drain the carburetor bowl. Keep the petcock closed. Hit the starter button, open the petcock and count to three, then shut off the petcock. The bike should have started and enough gas should have gone into the bowl to allow it to run for a bit. If not, do it again and count to five.

When the engine is running and the petcock is closed, see if it will operate normally in response to the throttle. It should. When it starts to falter as if it is running out of gas, open the petcock. Let it idle. If it floods, it is surely your inlet valve.

The inlet valve seat should be cleaned with a q-tip and a bit of polishing compound and the needle should be removed from the float and inspected. If it appears hardened or has a worn ring, replace it. If not, gently wipe it and reinstall it.

Don't mess with your idle mix needle until you have this flooding under control.

Thanks for another helpful reply Tom! Will give this a try tonight and let you guys know how it goes.


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post #9 of 10 Old 04-04-2020, 07:53 PM
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@pdwestman asked an important question, is the upper elbow plugged in some way?

The symptoms of fuel starvation and fuel flooding are similar; the engine runs like crap. It's important that you don't have two things going on at the same time or that our internet diagnosis is going n the wrong direction.

We had a case where a fella had fuel issues and he would take his carburetor off of the bike to do precision fuel level testing, then he'd put it back on the bike and it would run like crap. We finally figured out that he was capping the upper elbow when he put the carburetor back on. That upper elbow is a bowl vent; if it is obstructed no fuel can come into the carb.

If it was left to sit for a while enough fuel would dribble in so the bike would run for a bit. In your case, opening the bowl drain would have the same effect as letting it sit for a while.

Pay heed to Paul's question and make sure the vent is open and clear.

Tom [email protected]

“On the way downtown I stopped at a bar and had a couple of double Scotches. They didn't do me any good. All they did was make me think of Silver-Wig, and I never saw her again.” -Philip Marlowe

“'Why' and 'How' are words so important they cannot be too often used.” -Napoleon Bonaparte

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post #10 of 10 Old 04-12-2020, 04:08 PM Thread Starter
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Okay! As of this afternoon she is running great. Still need to take for a test ride (raining again the moment) to confirm but I think I should be good to go.

What I did:
1) Looked closer at my carb set up as it was. It turns out the inlet side rubber hose that slides over the carb was kinked a little and wasn’t actually properly sealed off (whoops).

2) I looked closer at the choke cable. It turns out either me (or optimistically the precious owner) has broke the plastic choke nut. It still seats the little choke needle and spring okay, but I think there’s a good chance I hadn’t properly seated it previously (much like the rubber inlet hose). I ordered a replacement brass that’s on its way.

3) I pulled all the vacuum lines, fuel lines, rubber hoses, etc and blew them clear with compressed air and made sure they weren’t blocked (also measure sure petcock let fuel flow w vacuum). Also checked the plastic elbows per advice to make sure they were okay!

4) I pulled the carb and instead of just doing a quick little clean I tore it all down, soaked in carb cleaner overnight, and brushed clean, blew passages clear, etc. One thing I discovered was that one of my jets had quite a few clogged orifices, despite me having “cleaned it” before. Also checked float height, which was good to go.

5) reinstalled carb. Made sure to seat hoses properly, etc. managed to get choke installed with my half broken plastic nut, planning to replace when I get the brass one.

6) tried to start. Per recommendations above, I tried opening petcock, counting to 3, and starting. This didn’t work (at first) and my battery was struggling, so I walked away and gave it some time. I did check however to make sure fuel made it into the float bowl from those few seconds. Good to go. Also checked and left petcock open and tried starting for a few more minutes and this time carb was no longer overflowing.

7) Gave it some time, tried starting again (full choke) voila! Perked right up and ran well. Let it run for a few minutes, up down throttle, etc. The only “off” thing is that it may be running a little rich, but I’m going to do a test ride before I move any further.

Just wanted to share in case others run into the same issues. Long story short: bad install on my half, could’ve been one of a few factors, slowing down and fully cleaning and trying again did the trick!


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